1. Field of the Invention
The present invention relates to semiconductor packages and fabrication methods thereof, and more particularly, to a semiconductor package having a sleeve member and a fan wheel and a fabrication method of the semiconductor package.
2. Description of Related Art
Circuit boards, for example, main boards or motherboards, include electronic components such as central processing units or graphic cards and conductive circuits electrically connecting the electronic components. During operation of the electronic components, heat generated by the electronic components must be dissipated to prevent the electronic components from failing due to overheating. Particularly, in electronic products having more functionalities and higher processing speeds, a large number of electronic components of higher levels are disposed on circuit boards of the electronic products for providing more functionalities and higher processing speeds. Accordingly, more heat is generated by the electronic components, which must be effectively dissipated so as to ensure normal operation of the electronic products.
Generally, heat dissipating fans are mounted on the main boards or motherboards for dissipating heat, as disclosed in U.S. Pat. No. 6,799,282, No. 7,215,548, No. 7,286,357, No. 7,568,517, No. 7,884,512 and No. 7,884,523.
FIG. 7A shows an example of a conventional heat dissipating fan mounted at a predefined position of a circuit board. The heat dissipating fan mainly consists of a printed circuit board 71, a housing 72 and a fan wheel 73. The housing 72 has a base 720, a sleeve 722 and a coil module 721 disposed around the sleeve 722. The fan wheel 73 has a hub 730, a magnet 731 disposed at an inner side of the hub 730, a plurality of blades 732 disposed around an outer side of the hub 730, and a shaft 733 axially connected to the hub 730 so as to be axially disposed in the sleeve 722. The printed circuit board 71 has at least a control chip 710 and a plurality of passive components 712. The printed circuit board 71 is disposed on the base 720 of the housing 72 such that rotation of the fan wheel 73 can be controlled by the control chip 710. Further, air flow is driven through rotation of the fan wheel 73.
However, since the control chip 710 is located in a narrow gap between the base 720 of the housing 72 and the hub 730 of the fan wheel 73, heat generated by the control chip 710 cannot be effectively dissipated, thus easily causing failing of the control chip 710 due to overheating. Once the control chip 710 fails, the fan wheel 73 cannot be operated by the control chip 710. As such, heat generated by the electronic components on the circuit board cannot be effectively dissipated, which can cause crashes and even damage of the electronic product.
Further, the size of the gap between the hub 730 of the fan wheel 73 and the base 720 of the housing 72 depends on the thickness of the control chip 710. If the thickness of the control chip 710 increases, the size of the gap must be increased, thus adversely affecting reduction of the overall height of the heat dissipating fan. Furthermore, since the circuit board 71 needs to have an increased area for disposing of the control chip 710, in the case the cross-sectional area of the heat dissipating fan is not changed, the blades 732 have a decreased area, thereby adversely affecting the output of air flow and the heat dissipating effect.
In view of the above-described drawbacks, U.S. Pat. No. 7,345,884 discloses an improved heat dissipating fan. Referring to FIG. 7B, a printed circuit board 71′ is provided, which has an extending portion 71a extending outwards so as for a control chip 710′ to be disposed thereon, thereby allowing the control chip 710′ to be completely or partially exposed from the gap between a base 720′ of a housing 72′ and a hub 730′ of a fan wheel 73′. As such, heat generated by the control chip 710′ can be effectively dissipated through air flow driven by the fan wheel 73′.
However, air flow driven by the fan wheel 73′ may be disturbed by the extending portion 71a of the printed circuit board 71′ so as to generate noises, thus adversely affecting the performance of the electronic product. Meanwhile, a predefined spacing must be maintained between the blades 732′ and the control chip 710′, which prevents reduction of the overall height of the heat dissipating fan and cannot meet the miniaturization demand of electronic products.
In addition, the printed circuit board 71′ disposed between the hub 730′ of the fan wheel 73′ and the base 720′ of the housing 72′ adversely affects the overall height of the heat dissipating fan and prevents miniaturization of the heat dissipating fan.